1.不使用图片的：

.QPushButton {
        background:qlineargradient(spread:pad, x1:0, y1:0, x2:0, y2:1, 
stop:0 rgba(233, 233, 233, 255), 
stop:0.35 rgba(220, 220, 220, 255), 
stop:0.5 rgba(213, 213, 213, 255), 
stop:0.65 rgba(230, 230, 230, 255), 
stop:1 rgba(242, 242, 242, 255));
 border: 1px solid rgb(128,126,126);
 border-radius: 5px;
}
.QPushButton:hover{
        background:qlineargradient(spread:pad, x1:0, y1:0, x2:0, y2:1, 
stop:0 rgba(250, 250, 250, 255), 
stop:0.5 rgba(255, 255, 255, 255), 
stop:1 rgba(250, 250, 250, 255));
 border: 1px solid rgb(63,140,161);
 border-radius: 5px;
}

.QPushButton:pressed{
        background:qlineargradient(spread:pad, x1:0, y1:0, x2:0, y2:1, 
stop:0 rgba(255, 255, 255, 255), 
stop:0.5 rgba(235, 247, 253, 255), 
stop:1 rgba(213, 237, 250, 255));
 border: 1px solid rgb(3,110,183);
 border-radius: 5px;
}

2.使用图片

QPushButton {
border-image: url(:/image/functionButtons/normal_button_hover.png);
}

.QPushButton:hover{
border-image: url(:/image/functionButtons/normal_button_pressed.png);
}

.QPushButton:pressed{
border-image: url(:/image/functionButtons/normal_button.png);
}