Abstract: The pollen viability of a transgenic rice, B68-1 containingbar gene with herbicide Basta resistance, was investigated under four temperatures (20℃, 25℃, 30℃, 35℃) and four kinds of humidity (30%, 50%, 70%, 90%) by 2,3,5-triphenyl tetrazolium chloride (TTC) method in vitro after 0, 1, 2, 3, 4, 5, 6, 8, 10, 12, 14 min from anther. The test showed that B68- 1 pollen viability decreased with passing time in vitro under various conditions, like“S curve”or its section, which could accurately described by the Logistic equation. In vitro, pollen viability first increased and then decreased with the rising temperature, and showed the same with humidity. 25℃ was the most optimum temperature in any determined humidity, and 70% humidity was the most optimum humidity in any determined temperature. High temperature stress on the pollen viability was more obvious than low temperature, and high humidity was more obvious than low. Two equations, an exponential one and a Logistic one, could give satisfied predicts of the pollen viability duration and pollen longevity, help to estimate the drift distance of transgenic pollen flow.