The spin improvement string pliers is a pivotally secured together plier device used to manually restructure and roughen the surface of a synthetic or a polyester string on a strung tennis racquet by means of plastic deformation. The line grids on the pliers depress the string, leaving a series of indentations on the string surface that increases the friction between the string and the ball so that the tennis player can more easily generate top or under spin on a tennis ball.