are two arches whose centers of circle are on both sides of the water spinning blade 3 respectively smooth transition can be realized between the first convex rib 31 and the second convex rib 32 central angle u03b1 between end a and end b of the water spinning blade 3 is 45 u00b0 60 u00b0 according to fig4 in this embodiment a height change of an upper surface of the water spinning blade 3 in extension direction from the center 5 of impeller disk to the edge is rising to the maximum height falling to the minimum height and then rising to realize smooth transition with the inner circumferential wall 4 of basin shaped impeller disk height difference h 1 between the maximum height and the minimum height of the water spinning blade is 1 2 1 3 times of the depth h of impeller disk height difference between the highest point of the water spinning blade and the center of the impeller disk is 0 1 times of the depth of the impeller disk point c of smooth transition between the water spinning blade 3 and the inner circumferential wall 4 of the impeller disk is located u2153 u2154 of the depth h of the impeller disk i e height difference h between point c and the lowest point of the impeller disk is u2153 u2154 times of the depth h of the impeller disk with u00bd times preferred according to fig3 multiple decoration areas 6 are set on the surface of the impeller disk between two water spinning blades 3 and these decoration areas are provided with small water penetrating holes 7 the decoration areas are water mark shaped shallow slots with different sizes with depth of 2 mm multiple small water penetrating holes are distributed evenly in.