The invention discloses a variable pitch method for a tidal current energy generating set. The variable pitch angle of the tidal current energy generating set ranges from 0 degree to 270 degrees. The method comprises the steps that the full feathering angle of forward incoming currents is set to be 0 degree, the angle for capturing the maximum energy of the forward incoming currents is set to be 90 degrees, the full feathering angle of reverse incoming currents is set to be 180 degrees, and the angle for capturing the maximum energy of the reverse incoming currents is set to be 270 degrees; in the condition of the forward incoming currents, oar blades are set at 0-90 degrees to conduct power adjustment; in the condition of the reverse incoming currents, the oar blades are set at 180-270 degrees to conduct power adjustment. According to the variable pitch method for the tidal current energy generating set, the bidirectional variable pitch is adopted, it is ensured that the generating set can work in the bidirectional tidal currents by rotating the blades by 0-270 degrees, the tidal current energy is fully captured, application is conducted flexibly, the energy capture efficiency can be improved, and the power generation capacity can be increased.