Abstract: A study of certain factors affecting the induction and differentiation of wheat pollen callus cultured in vitro has been made. The results arc summarized as follows: 1. Sucrose in the medium plays an important role as the source of carbon and the regulator of osmotic pressure. The optimum concentration of sucrose is 10%. 2. Casein hydrolysate is obviously beneficial to the callus formation, the subsequent differentiation of organs and the diploidization of chromosomes. 3. When the spike of the wheat is pretreated at 3–5 ℃ for 48 hours, the frequency of induction is greatly increased. 4. Higher temperature may promote the callus induction and the ability of organ differentiation. 5. Genotypic differences have a definite effect on the induction frequency of the pollen plantlets.