1.使用系统自带api

    ui->pushButton->setIconSize(QSize(32,32));
    ui->pushButton->setIcon(QIcon(":/images/Setting.png"));
    ui->pushButton->setText(QString::fromLocal8Bit("系统设置"));
    ui->pushButton->setStyleSheet("QPushButton{border:1px solid blue;background:white;}"
                                  "QPushButton:hover{border:0px;background:blue;}"
                                  "QPushButton:pressed{border:0px;background:red;}");

 无法设置icon和文字之间的距离。

2.如果想让icon显示在文字上方可使用QToolButton

ui->toolButton->setIconSize(QSize(32,32));
    ui->toolButton->setIcon(QIcon(":/images/Setting.png"));
    ui->toolButton->setText(QString::fromLocal8Bit("系统设置"));
    ui->toolButton->setToolButtonStyle(Qt::ToolButtonTextUnderIcon);

3.在pushbutton上面使用label进行布局

 QLabel *iconLabel = new QLabel;
    QLabel *textLabel = new QLabel;
    iconLabel->setFixedSize(32,32);
    iconLabel->setStyleSheet("border:1px solid red;");
    textLabel->setStyleSheet("border:1px solid red;");
    iconLabel->setPixmap(QPixmap(":/images/Setting.png"));
    textLabel->setText(QString::fromLocal8Bit("系统设置"));
    textLabel->setFixedWidth(60);
    QHBoxLayout *myLayout = new QHBoxLayout();
    myLayout->addSpacing(10);
    myLayout->addWidget(iconLabel);
    myLayout->addSpacing(30);
    myLayout->addWidget(textLabel);
    myLayout->addStretch();
    ui->pushButton_2->setLayout(myLayout);
    ui->pushButton_2->setStyleSheet("QPushButton{border:1px solid blue;background:white;}"
                                  "QPushButton:hover{border:0px;background:blue;}"
                                  "QPushButton:pressed{border:0px;background:red;}");

4.使用图片，设置stylesheet即可

以上三种方法，需要设置，比较麻烦，最好还是找UI设计按钮图片，这样软件的适配性也比较好。