A centrally mounted driving mechanism applicable to a power-assisted bicycle, comprising: a housing; a motor configured for providing a driving force; a planetary gear mechanism in transmission connection with a motor output shaft; a bevel gear driving end (9, 9A); a bevel gear driven end engaged with the bevel gear driving end (9, 9A), wherein the bevel gear driven end is connected with a crankset, and the planetary gear mechanism comprises a planetary gear and a planetary gear output bracket (5, 5A); and wherein the centrally mounted driving mechanism further comprises a bevel gear support (8, 8A) sleeved outside the planetary gear output bracket (5, 5A), a clutch is provided between the planetary gear output bracket (5, 5A) and the bevel gear support (8, 8A), and the planetary gear output bracket (5, 5A) is in transmission connection with the bevel gear support (8, 8A) through the clutch; the bevel gear driving end (9, 9A) is coaxially and fixedly connected with the bevel gear support (8, 8A), and a support assembly (7, 7A) is provided outside the bevel gear support (8, 8A), and the support assembly is configured to support the planetary gear output bracket (5, 5A) and the bevel gear driving end (9, 9A); the planetary gear output bracket (5, 5A) has a shaft portion (51, 51A), the bevel gear support (8, 8A) has a second annular protrusion (82, 82A), and the second annular protrusion (82, 82A) is configured to surround the shaft portion (51, 51A); the clutch (6, 6A) is arranged between the second annular protrusion (82, 82A) and the planetary gear output bracket (5, 5A), and the clutch (6, 6A) is fitted with and connected to the bevel gear support (8, 8A) and the planetary gear output bracket (5, 5A), to realize connection and separation of the bevel gear support (8, 8A) and the planetary gear output bracket (5, 5A); and the support assembly (7, 7A) is arranged outside the second annular protrusion (82, 82A); characterized in that, the bevel gear support is provided with a first annular protrusion located at an inner side of the second annular protrusion, the bevel gear driving end is connected to an inner wall of the first annular protrusion; and a groove is provided at an end of the shaft portion away from the planetary gear, the first annular protrusion is inserted into the groove, and a gap is provided between the first annular protrusion and an inner wall of the groove. a housing; a motor configured for providing a driving force; a planetary gear mechanism in transmission connection with a motor output shaft; a bevel gear driving end (9, 9A); a bevel gear driven end engaged with the bevel gear driving end (9, 9A), wherein the bevel gear driven end is connected with a crankset, and the planetary gear mechanism comprises a planetary gear and a planetary gear output bracket (5, 5A); and wherein the centrally mounted driving mechanism further comprises a bevel gear support (8, 8A) sleeved outside the planetary gear output bracket (5, 5A), a clutch is provided between the planetary gear output bracket (5, 5A) and the bevel gear support (8, 8A), and the planetary gear output bracket (5, 5A) is in transmission connection with the bevel gear support (8, 8A) through the clutch; the bevel gear driving end (9, 9A) is coaxially and fixedly connected with the bevel gear support (8, 8A), and a support assembly (7, 7A) is provided outside the bevel gear support (8, 8A), and the support assembly is configured to support the planetary gear output bracket (5, 5A) and the bevel gear driving end (9, 9A); the planetary gear output bracket (5, 5A) has a shaft portion (51, 51A), the bevel gear support (8, 8A) has a second annular protrusion (82, 82A), and the second annular protrusion (82, 82A) is configured to surround the shaft portion (51, 51A); the clutch (6, 6A) is arranged between the second annular protrusion (82, 82A) and the planetary gear output bracket (5, 5A), and the clutch (6, 6A) is fitted with and connected to the bevel gear support (8, 8A) and the planetary gear output bracket (5, 5A), to realize connection and separation of the bevel gear support (8, 8A) and the planetary gear output bracket (5, 5A); and the support assembly (7, 7A) is arranged outside the second annular protrusion (82, 82A); characterized in that, the bevel gear support is provided with a first annular protrusion located at an inner side of the second annular protrusion, the bevel gear driving end is connected to an inner wall of the first annular protrusion; and a groove is provided at an end of the shaft portion away from the planetary gear, the first annular protrusion is inserted into the groove, and a gap is provided between the first annular protrusion and an inner wall of the groove.