Abstract: [Objective] Through the culture of seed-watermelon pollen,the effects of different concentrations of sucrose and boric acid as basic liquid medium at different culture temperatures and in different culture time on pollen germination in vitro are studied.[Method]In this project,the optimum culture medium was used to carry out in vitro culture at 6 temperature levels and at 4 time levels.[Result]When the culture temperature was 25-30,the highest pollen viability was obtained,and the optimal medium formula was: 15;sucrose,0.01;boric acid and 1;agar.[Conclusion]With the increased temperature,the germinal rates of pollen and the length of pollen tube were increased;when the temperature reached up to 30℃,the pollen germination rates and pollen length were both decreased.In addition,the germination rate and pollen length were increased by being cultured for 4 hours,and then the length was no longer increased after being cultured 6 hours at room temperature.