Under the new development pattern of dual cycles, enterprises should take innovation as the basis to treat the transformation and development of the new international and domestic situation. As an important pillar of the national economy, it is of great significance to promote the innovation and development of small and micro enterprises to expand employment and improve people's livelihood. However, the problem of difficult financing and expensive financing hinders the innovation and development of small and micro enterprises. At present, the research on the combination of financing and innovation and development of small and micro enterprises is still very lacking. This article uses data from the China Micro Enterprise Survey (CMES) to empirically test the impact of formal financing from banks and credit cooperatives and informal financing from private loans on the R&D innovation of micro enterprises. The results show that loans from formal financial institutions can help promote micro enterprises to carry out R&D and innovation activities and increase their investment in R&D and innovation. Loans from informal financial institutions will inhibit the R&D and innovation of micro enterprises to a certain extent. Based on this, policy recommendations for alleviating capital constraints to promote the innovative development of micro enterprises have been proposed from both financial institutions and micro enterprises.