Microenvironment fluctuations are a natural phenomenon occurring during cellular transcription expression, providing a weak background for biochemical molecular noise. The effectiveness of trans-differentiation induced by reprogramming factors heavily depends on microenvironmental conditions. To elucidate this mechanism, we developed a theoretical framework that combines single promoter switching models with cell fate decision promoter coupling circuits, utilizing the large deviation method to quantify the influence of microenvironment on cell phenotype transitions. Our results demonstrate that asymmetric differentiation trends in internal gene circuits can be determined by symmetric microenvironmental conditions. Consistent with Monte Carlo simulations, our theory provides a pathway for controlling stochastic systems through stochastic signal inputs