要使用Python畫動態圣誕樹，可以使用turtle庫來繪制圖形，并結合時間模塊來實現動態效果。

以下是一個簡單的示例代碼：

import turtle
import time

# 設置畫布大小和背景顏色
turtle.setup(800, 600)
turtle.bgcolor("black")

# 創建畫筆
pen = turtle.Pen()
pen.speed(0)  # 設置繪制速度

# 定義圣誕樹的參數
tree_height = 200
tree_width = 250
tree_layers = 5

# 繪制樹干
def draw_trunk():
    pen.color("brown")
    pen.begin_fill()
    pen.left(90)
    pen.forward(tree_height)
    pen.right(90)
    pen.forward(40)
    pen.right(90)
    pen.forward(tree_height)
    pen.right(90)
    pen.forward(40)
    pen.end_fill()

# 繪制圣誕樹的一層
def draw_tree_layer(layer_height, layer_width):
    pen.color("green")
    pen.begin_fill()
    pen.left(90)
    pen.forward(layer_height)
    pen.right(135)
    pen.forward(layer_width / 2)
    pen.left(90)
    pen.forward(layer_width / 2)
    pen.right(135)
    pen.forward(layer_height)
    pen.end_fill()

# 繪制整棵圣誕樹
def draw_tree():
    pen.penup()
    pen.goto(0, -250)  # 定位到畫樹干的起始位置
    pen.pendown()
    draw_trunk()  # 繪制樹干
    pen.penup()
    pen.goto(-tree_width / 2, -250 + tree_height)  # 定位到樹層的起始位置
    pen.pendown()
    for i in range(tree_layers):
        draw_tree_layer(tree_height / tree_layers, tree_width - i * (tree_width / tree_layers))  # 繪制每一層樹枝
        pen.penup()
        pen.goto(-tree_width / 2, -250 + tree_height + (i + 1) * (tree_height / tree_layers))  # 更新下一層的起始位置
        pen.pendown()

# 主程序
while True:
    pen.clear()  # 清空畫布
    draw_tree()  # 繪制圣誕樹
    time.sleep(0.5)  # 等待0.5秒
    pen.reset()  # 重置畫筆

運行以上代碼，就可以看到繪制出來的動態圣誕樹。每隔0.5秒，畫布會被清空，然后重新繪制圣誕樹，形成動態效果。