代码

from tkinter import *
from tkinter import ttk

select = {"年度": ("第一季度", "第二季度", "第三季度", "第四季度"),
          "第一季度": ("1月", "2月", "3月"),
          "第二季度": ("4月", "5月", "6月"),
          "第三季度": ("8月", "7月", "9月"),
          "第四季度": ("10月", "11月", "12月")}


class Perf_GUI():
    def __init__(self, init_window_name):
        self.init_window_name = init_window_name

    def init_window(self):
        self.init_window_name.title("二级菜单联动")  # 设置窗口名字
        self.init_window_name.geometry('770x520+100+50')  # 设置窗口大小

        self.plan_period_label = Label(self.init_window_name, text="一级菜单:")
        self.plan_period_label.grid(row=1, column=0)
        xVariable = StringVar()
        self.plan_ttk = ttk.Combobox(self.init_window_name, textvariable=xVariable)
        self.plan_ttk.grid(row=1, column=1)
        self.plan_ttk['value'] = list(select.keys())
        self.report_period_label = Label(self.init_window_name, text="二级菜单:")
        self.report_period_label.grid(row=1, column=2)
        der = StringVar()
        self.report_ttk = ttk.Combobox(self.init_window_name, textvariable=der)
        self.report_ttk.grid(row=1, column=3)

        # Combobox下拉菜单实现联动
        def xFunc(event):
            self.report_ttk.delete(0, END)
            value = xVariable.get()
            self.report_ttk['value'] = select[value]

        self.plan_ttk.bind("<<ComboboxSelected>>", xFunc)


def gui_start():
    init_window = Tk()
    Gui_Tool = Perf_GUI(init_window)
    Gui_Tool.init_window()
    init_window.mainloop()


if __name__ == '__main__':
    gui_start()

效果图

一级菜单选择年度时：

一级菜单选择第一季度时：