Abstract: Plant-based meat has brought numerous challenges to traditional 3D printing. Among them, the plant protein-based meat (PPM) has also been produced with a loose texture and reduced chewiness, due to the insufficient protein cross-linking. This study aims to optimize the rheological and forming properties of the plant protein ink using high-moisture extrusion (HME). A systematic investigation was also implemented to explore the impact of the HME processing parameters on the product quality. Thereby, the texture limitations of the 3D-printed PPM were overcome for the highly realistic PPM. The soy protein isolate, wheat gluten, and potato starch were selected as the raw materials. A twin-screw extruder was then used to prepare the plant-based protein ink in the HME pretreatment (moisture content of 60%). An analysis was also made to clarify the effects of the HME pretreatment on the rheological properties and moisture distribution of the ink. In the experiment, the ink without HME pretreatment was set as the control group (CG). The ink subjected to HME pretreatment at the different cooking temperatures (160-200 °C, with a temperature gradient of 10 °C, totaling five groups) was set as the experimental group. A rotational rheometer was used to measure the yield stress, shear viscosity, storage and loss modulus, as well as the thixotropic recovery rate of each ink group; A halogen moisture analyzer was used to determine the moisture content of the ink; And a food 3D printer was used to print the PPM samples. The rheometer's texture profile analysis (TPA) function was used to measure the texture parameters of the samples, including the hardness, elasticity, and chewiness. A single-blade shear test was carried out to assess the organization level of the samples. A scanning electron microscope (SEM) was used to characterize the microstructure, porosity, and fiber orientation of the samples. Additionally, the 3D printing formability of the ink was also investigated after optimization. The results showed that the HME altered the rheological properties of the ink. The viscosity, storage modulus, and loss modulus were enhanced in the experimental group, compared with the CG, indicating the improved solid sample behavior and structural integrity. The thixotropic recovery rate decreased from 83.0% in the CG to 41.6%-70.7% in the experimental group. The 3D printing extrusion was smoother for the regulatory requirements on the HME self-healing after extrusion. Moisture content tests indicated that the HME treatment at 170-200 °C significantly dominated the moisture state of the ink. Texture parameters exhibited an outstanding temperature dependence. Once the samples were treated at 180 °C, there was an increase in the hardness, elasticity, and chewiness of 182.38%, 206.02%, and 1 542.65%, respectively. Microscopic structural analysis indicated that the HME promoted the dissolution of the raw materials and the porosity of the printed PPM. The HME technology effectively improved the rheological properties and printing accuracy of the ink. The intermolecular disulfide bonds and hydrogen bonds were regulated with a cooking temperature of 180 °C, in order to maximize the texture enhancement. Additionally, 3D printing forming performance experiments of the PPM further validated that the HME treatment at specific temperatures enhanced the 3D printing accuracy of the PPM. The synergistic mechanism between HME and 3D printing can provide an innovative technical solution to overcome the problems, such as the low fiber content and monotonous texture in the PPM products. The finding can also offer the theoretical support and technical reference for the customized plant-based meat products.