Abstract: The present situation and technical levels of fertilizer applicators at home and abroad were reviewed. On the basis of extensive study, the authors have developed the fertilizer applicator according to Chinese conditions. It is equipped with high-accuracy EC/pH sensors, hydrometer with electric pulse, service valve, pressure gauge, plastic filter and fertilizer pumps. The machine was designed in modulus, the pressure and amounts of fertilizer, and EC/pH value could be adjusted to meet different needs of users. It has characteristics of high-utilization ratio of fertilizer, high precision, convenient operation and perfect breakdown alerting system. It can be used in greenhouses, orchards or gardens. The fertilizer applicator has been realized as products and has been granted with Chinese patent. The fertilizer applicator plays important roles in production of protected agriculture.