Abstract: ASL is a new kind of plant growth regulators prepared from alkaline pulping liquor of wheat straw. The repeated application and appraisal at different areas for many years showed that ASL can increase production steadily for various kinds of crop. Its main effect can be reduced to three:(1) to accelerate the function of meristem (2) to promote the photosynthesis of plant (3) to enhance stress resistance. It shows a wide application perspective in agriculture and forestry.