Compared with comprehensive Q&A communities, vertical Q&A communities have more obvious technical, social, intellectual, marketing and scene characteristics. Based on the theory of planning behaviour and the technology acceptance model, a structural equation model of users' willingness to use is constructed by taking tourism Q&A communities as an example, which is helpful to understand the influence mechanism of users' attitude and willingness to use in vertical Q&A communities, and then improve the quality of community knowledge and improve the difficulties of community business operation. This study proves that the users' perceived usefulness, usage attitude, subjective behaviour norms and perceived behaviour control have a positive and significant impact on usage intention. At the same time, ease of use, perceived usefulness and attitude of use have indirect mediating effect on the influence path of intention to use. Finally, the research puts forward some suggestions to improve the sustainable use intention of tourism Q&A community users from the aspects of improving the quality of content, encouraging the production and dissemination of high-quality content, strengthening social attributes, improving community identity, and mining community value.