Potamogeton pectinatus L., with extensive adaptability, is a perennial submerged aquatic macrophyte.It can survive in hyer-eutrophic waters.The results show that net photosynthetic rate at 10℃ was 0.88mg/(g·h) and its optimum temperature was at 25℃.Poor growth was found at 30℃.In Dianchi Lake, the maximal net photosynthetic rate fell in January to March and minimal value occurred in June.This species can regulate content of chlorophyll a and b to use light better.The light compensation point in P.pectinatus 358 to 1256Lx, depends on temperature.