Non-timber forest products (NTFPs) include all plant materials other than timber, such as seeds, flowers, fruits, leaves, roots, bark, latex, resins, and other non-wood plant parts. The significant role of NTFPs in improving local people's lives and forest biodiversity conservation has been widely accepted. However, many studies in past decades indicated that NTFPs utilization had various ecological effects on different levels, from plant individual and population to community and forest ecosystem, depending not only on the plant parts extracted and their biological or ecological attributes, but also on the harvest forms. This paper reviewed the research progress about the effects of the utilization of NTFPs from biological and ecological aspects, and discussed some research problems and research priorities.