Shield tunneling machine starting method

The invention relates to a shield tunneling machine starting method. The method comprises the following steps that preparation work of a shield starting well is conducted; a cutter head of the multi-mode shield tunneling machine is pushed into a sealing device, and the sealing device is completely and tightly attached to a machine shell of the multi-mode shield tunneling machine; a filler corresponding to the current tunneling mode is selected to backfill a sealed cabin of the multi-mode shield tunneling machine; when the multi-mode shield tunneling machine carries out tunneling construction, pressure is gradually established in the sealed cabin until the multi-mode shield tunneling machine passes through a tunnel portal and a shield pressure balance state is established; and after the multi-mode shield tunneling machine enters an end soil body, the multi-mode shield tunneling machine is switched to a corresponding tunneling mode according to the geological condition of the end soil body. According to the shi