The invention discloses a heat exchanger of a shell pass integral wrapped shell structure. A heat exchanger used at present is not provided with a corresponding heat exchanging pipe protection structure at a medium inlet, and media easily corrode a shell at the position where a wrapped shell is not arranged. The heat exchanger comprises a shell pass integral wrapped shell which comprises a half wrapped shell (1), the half wrapped shell is connected with a left wrapped shell (2), the half wrapped shell is connected with a right wrapped shell (4) through a baffle (3), the upper portion of the right wrapped shell is connected with a medium inlet connecting device (5), the lower portion of the right wrapped shell is connected with a medium outlet connecting device (6), the part, corresponding to the left wrapped shell, of the medium inlet connecting device is provided with a stainless steel impingement plate (8), a transverse partition board (9) and a baffle plate (10) are arranged inside the half wrapped shell. A cavity chamber is formed by the transverse partition board, a pipe plate (11), the half wrapped shell, the left wrapped shell and the right wrapped shell, and the transverse partition board is connected with the pipe plate. The heat exchanger is used for power station water heat exchangers.