The invention discloses an open cutting construction method of a shield tunnel transverse connection channel. The method comprises the steps that firstly, a first underground continuous wall and a second underground wall are driven around the periphery within the range of the transverse connection channel prepared to be excavated in a manner of extending to a left line shield tunnel and a right line shield tunnel; secondly, a shield tunneling machine is adopted to cut and break the second underground continuous wall in the left line shield tunnel and the right line shield tunnel, and a shieldsegment structure is erected and spliced in the left line shield tunnel and the right line shield tunnel; thirdly, a foundation pit is subjected to open cutting from the ground surface to the bottom,and foundation pit supporting is applied layer by layer; fourthly, a left line upper shield segment and a right line upper shield segment are removed; fifthly, a main hole tunnel frame structure in the left line shield tunnel and the right line shield tunnel and a frame structure in the transverse connection channel are applied; and sixthly, earth above the main hole tunnel frame structure and thetransverse connection channel frame structure is subjected to backfilling, the foundation pit supporting is removed, and the condition ground is recovered. The method has the advantages of being lowin construction risk and low in engineering cost.