In our study, we used several kinds of organic solvents of droplets in different environmental humidity to compare the process of droplet evaporation, and especially to observer the change of the droplet contact angle. The organic solvents we used are: methanol, acetone, iso-propanol, toluene, and cyclohexane. We found that the methanol evaporation behaviors in high humidity and low humidity were different. In high humidity, the evaporation process showed four stages: up - down - up to maximum value - slowly down. The change of the contact angle in low humidity presented two stages: up - down. It could be explained by that water was absorbed into the methanol droplet in high humidity. The change of the contact angle of the acetone droplet in high humidity showed three stages: flat - up - slowly down. It is different from the change of the contact angle of the methanol droplet. It might be because the viscosity coefficient of acetone is much smaller than that of methanol. The contact angle of the acetone droplet is close to its dynamic equilibrium value. The evaporation of the iso-propanol droplet was similar to that of the methanol droplet. However, the evaporation rate of iso-propanol is lower than that of methanol, so the stage transition of the contact angle occured later. The evaporation of the toluene and cyclohexane droplets showed that the humidity did not affect their evaporation.