【Objective】To explore the responses of “Chinese long” sequenced cucumber genotype to different phosphorus (P) availability, and to screen an optimal low-P-treatment concentration for cucumber germplasms screening for P efficiency under a hydropoic condition. 【Method】 Hydroponic culture was used to test effects of different P availability on the growth and P absorption of “Chinese Long”. 【Result and conclusion】 The results showed that with the decrease in P availability, cucumber plants became shorter and smaller, and new leaves became smaller and old leaves became yellow. Severe P deficiency (10 and 1 μmol·L^-1) significantly inhibited the cucumber plant growth, even resulting in abnormal fruits. Low P availability decreased the biomass and P uptake efficiency of “Chinese Long”, but increased its ratio of root to shoot, which preferably allocated carbonhydrate to root. Furthermore, under P deficiency, “Chinese Long” also formed finer roots with a small root diameter, thus increasing the contact area with nutrients in the growth medium. The P concentration of 10-100 μmol·L^-1, for example 50 μmol·L^-1, can be used to screen the cucumber germplasms for P efficiency.