Abstract: Cold-start performance has been one of the most restricting factors in the internal combustion power equipment at in extreme cold conditions in plateau areas. The aim of this study was to explore the cold-start characteristics of diesel engines at different ambient temperatures in a plateau. Different strategies of fuel injection were then evaluated for the environmental adaptation. The research object was taken as the diesel engine with direct injection, high-pressure, and common rail. A test chamber with a low-temperature environment and a cold-start test bench were constructed on at the an altitude of 2 2,000 m. Then, the environmental adaptation experiments were carried out using 3 injection strategies at extreme cold conditions (the lowest ambient temperature was -45 ℃) in the plateau. The cold-start performances of diesel engines were evaluated with the different advanced angles of fuel injection. The results showed that the double injection (DI) and triple injection (TI) strategies were effectively improved the speed stability and reliability of the diesel engine cold-start in extreme conditions, compared with the single injection (SI) strategy. Furthermore, the strategies of fuel injection were ranked in the ascending order of TI < DI < SI, according to the delay timing of the combustion mean ignition. While the mean maximum combustion pressure was ranked in the opposite direction. Specifically, the longest delay of combustion ignition was observed in the SI strategy under cold-start conditions without the assistance of a glow plug, where the ignition delay was 4.5 ℃A after the top dead center. The ignition delay of the TI strategy was advanced by 5.6 ℃A, compared with the SI strategy, indicating the enhanced proportion of pre-mixed combustion. And tThen the uniform, stable, and high performance was achieved in the cold-start combustion of the diesel engine with the TI strategy. The optimal advance angle of fuel injection appropriately increased for the combustion of cold-start, which was 30 °CA BTDC. The largest peak of HC emission was generated by the diesel combustion using the SI strategy, while the middle and smallest peaks were found using the DI and TI strategy, respectively. Among them, the peak of HC emissions that generated by diesel combustion with the TI strategy decreased by 58.6% and 64.8% at 20 and -5 °C, respectively, compared with the SI strategy. The engine was started unsuccessfully at the temperatures of -25 °C and below for the SI strategy and -45 °C for the DI strategy. By contrast, the TI strategy was enabled on the engine cold-start performance in at one time in a wide temperature range of -45~20 °C. Particularly, the cold-start success rate was significantly improved for the average acceleration, in order to shorten the cold-start duration. Therefore, the diesel engine cold-start time of the SI strategy was the longest, the DI strategy was in the middle, and the TI strategy was the shortest under the cold-start conditions of consistent temperature. TI strategy was greatly improved the cold-start performance and environmental adaptation of the diesel engine under extreme cold conditions in the plateau. The research findings can also provide a strong reference to improve the cold-start performance and environmental adaptation of internal combustion power equipment under the a wide range of ambient temperatures in multiple regions.