The present invention provides a printing head comprising a plurality of sub-heads each comprising a base and a plurality of diversion trenches provided in the base, and one end of each of the diversion trenches is connected to one of nozzles of the sub-head. Projections of all the diversion trenches on a first plane in a first projection direction are arranged at an equal interval, the first plane is a plane defined by an arrangement direction and a length direction of the diversion trenches in the sub-head, and the first projection direction is a moving direction of the printing head with respect to a printing surface during printing. The spacing of the diversion trenches in each of the sub-heads is greater than that of the projections of all the diversion trenches in the first plane on the first projection direction.