要在Python中使用PyQt5庫為QPushButton實現拖拽功能，你需要重寫mousePressEvent、mouseMoveEvent和mouseReleaseEvent方法。以下是一個簡單的示例：

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QPushButton
from PyQt5.QtCore import Qt, QPoint

class DraggableButton(QPushButton):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.dragging = False
        self.offset = QPoint()

    def mousePressEvent(self, event):
        if event.button() == Qt.LeftButton:
            self.dragging = True
            self.offset = event.pos()
        super().mousePressEvent(event)

    def mouseMoveEvent(self, event):
        if self.dragging:
            self.move(self.pos() + event.pos() - self.offset)
        super().mouseMoveEvent(event)

    def mouseReleaseEvent(self, event):
        self.dragging = False
        super().mouseReleaseEvent(event)

class MainWindow(QWidget):
    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):
        self.setGeometry(300, 300, 400, 200)
        self.setWindowTitle('Draggable Button')

        self.button = DraggableButton('Drag me', self)
        self.button.move(100, 100)

if __name__ == '__main__':
    app = QApplication(sys.argv)
    main_window = MainWindow()
    main_window.show()
    sys.exit(app.exec_())

這個示例創建了一個名為DraggableButton的自定義按鈕類，它繼承自QPushButton。我們重寫了mousePressEvent、mouseMoveEvent和mouseReleaseEvent方法，以便在按下、移動和釋放鼠標按鈕時更新按鈕的位置。在MainWindow類中，我們創建了一個DraggableButton實例并將其添加到窗口中。運行此代碼將顯示一個包含可拖拽按鈕的窗口。