During the flare of hard X-ray transient source A0535 + 26 (December 1977),its optical and X-ray luminosity are non-synchronous.X-ray luminosity reached maximum about ten days later than optical luminosity did.The model of sporadic stellar wind increase of hard X-ray transient sources is discussed.The variable optical luminosity caused by the variable stellar wind is examined.The phenomenon of non-synchronism is explained in terms of this model.These come to the conclusion that the model may be reasonable