The blocked solvent-free polyurethane is mainly composed of hydrogenated phenylmethane diisocyanate (H12MDI) and polyester diol 2000, using methyl ethyl ketone oxime (MEKO) and caprolactam as blocking agents and dibutyltin dilaurate (DBTD) as catalyst. The blocked Solvent – free Polyurethane(SFPU) film was prepared by a prepolymer blocking method. The deblocking temperature and thermal properties of the blocked SFPU membrane were investigated by TGA and DSC. The effects of different sealers, leveling agents, catalyst dosage, oven temperature and blocking ratio on the deblocking temperature of the blocked SFPU, the curing conditions of the blocked SFPU and the film forming properties were investigated. The results showed that the deblocking temperature of the blocked SFPU with MEKO as a blocking agent was 143 ° C and the deblocking temperature of the blocked SFPU with caprolactam as a blocking agent was 163 ° C by differential scanning calorimetry (DSC).TGA analysis showed that at the same deblocking temperature, the blocking speed of the blocked SFPU with MEKO as the blocking agent was significantly higher than that of the blocked SFPU with caprolactam as the blocking agent. Under suitable curing conditions(The oven temperature is 140 ° C, the leveling agent mass fraction is 5%, and the catalyst mass fraction is 5‰. ), the blocked SFPU can be cured into a film, and the lower the blocking ratio of the blocked SFPU, the higher the curing temperature, the shorter the initial film forming time and the complete curing time of the blocked SFPU. From the five percentage closure gradients of 75%, 80%, 85%, 90%, 95%and100%, the mechanical properties of the membrane increased with the increase of the blocking ratio.