This paper reports results from cold shock and Cytochalasin B treatment experiments designed to induce triploidy in Chinese shrimp, P. orientalis, One of the most important commercial species in China. Three major factors influencing the rate of triploids and hatching were analysed respectively to seek for the most suitable treatment conditions. Ploidy was assessed by counting the number of polar bodies associated with early embryos and the number of chromosome in appendage-budding stage. Bect results were achicved with cold shock (at 4℃ for 30min administered 7 min after spawning) or with cytochalasin B at 0.25mg/L (administered 22 to 32 min after spawning ). The triploidy percentages were 70% by cold shock and 48% by cytochalasin B treatment. Orthogonal analysis indicated that hatching rates were affected significantly by duration and temperature (for treatment by cold shock) and by dosage and duration (for treatment with cytochalasin B).