The invention discloses a tidal current energy generator set and a generator rotation direction controlling and monitoring method thereof. The tidal current energy generator set is of a horizontal axis type, and a variable-pitch generator positive and negative rotation system with the pitch ranging from 0 degree to 270 degrees is adopted. The method includes the steps that if the mean direction offlow within a short period of time is between 0 degree and 180 degrees and the pitch angle of the generator set is between -5 degrees and 95 degrees, a master control system gives an instruction to aconverter to control the rotation speed direction of a generator to be the anticlockwise positive direction, and if the mean direction of flow within a short period of time is not between 0 degree and 180 degrees and the pitch angle of the generator set is between 175 degrees and 275 degrees, the master control system gives an instruction to the converter to control the rotation speed direction of the generator to be the clockwise negative direction; and further judgment can be made by comparing a generator positive and negative rotation instruction given by the master control system with thegenerator rotation direction actually fed back by a generator encoder. The tidal current energy generator set and the generator rotation direction controlling and monitoring method solve the problemof automatically controlling and monitoring the generator rotation direction of the tidal current energy generator set during tide rising, tide falling and slack tide, safe and stable running of the generator set is achieved, and the tidal current energy generator set and the generator rotation direction controlling and monitoring method are suitable for application and popularization.