In nucleation process of thin film growth, stable clusters will gradually cover substrate surface. The growth will occur in the covered parts of substrate, and the nucleation will proceed in the uncovered parts. In this paper, we investigate the influence of coverage on nucleation and growth of thin films and give a series of revised formulae for the widely used theory of thin film growth. We get that the nucleation rate is proportional to the square of uncovered area. It looks rough that the nucleation rate is considered to be a constant in thin film theories.