Abstract This paper is aimed at evaluating characteristics of R32/R1234ze(E) cloud explosion. The flame morphologies and explosion pressure are obtained experimentally and the laminar burning velocity is analyzed thermally and chemically. The results indicated that with the increase of equivalence ratio, the limiting oxygen content of xE=10% decreases monotonously, but the limiting oxygen content of xE=20% decreases firstly and then increases. The destabilization effect of hydrodynamic instability continues to reduce with the decrease of oxygen content. For various equivalence ratios and R1234ze (E) contents, a significant color difference is observed due to the formation of carbon particle and CH radical. As the oxygen content decreases, due to the decrease of laminar burning velocity, the maximum explosion pressure, maximum rate of pressure rise, positive pressure impulse and negative pressure impulse continue to decrease. The elementary reactions of greatly affecting laminar burning velocity are consisted of R1, R904, R925 and R963.