[Objective] In order to explore the mechanism of combined inoculation mi- croorganisms in improving coastal saline soil property and plant growth. [Method] The pot experiment was used to assess the effects of different inoculated proportion of arbuscular mycorrhizal fungi (AMF) and Phosphate-sotubilizing fungus. Apophysomyces spartina, on growth, chlorophyll contents, P-uptake of castor bean (Ricinus communis L.) and rhizosphere soil pH values, available P concentrations, enzyme activities. [Result] The mixed inoculation of AMF and A. spartina significantly reduced soil pH value, increased soil available phosphorous contents, improved the activities of soil invertase, urease, neutral phosphatase, and alkaline phosphatase. Chlorophyll contents, P-uptake, and plant dry weight of castor bean were also in- creased. The optimal proportion of the number of AMF spores to A. spartina colonies was 28.56:11.5×10^5, which had positive effects on saline soil and could stimulate plant growth under greenhouse condition. [Conclusion] Appropriate propor- tion of AMF and A. spartina had the potential to enhance coastal saline soil prop- erty and promote castor bean growth.