The invention discloses a crankshaft mounting structure of an opposed engine. The crankshaft mounting structure comprises a crankshaft. The crankshaft is sleeved and connected with a bearing pedestal capable of being detached into a left half bearing body and a right half bearing body. Semicircular bearing bushes are mounted between the inner walls of the left and right half bearing bodies and the crankshaft correspondingly. A full-through annular oil groove is formed in the inner wall of the bearing pedestal. Two bearing pedestal oil ways are arranged in the bearing pedestal centrosymmetrically and enable cylinder block oil ways to communicate with the annular oil groove. Bearing bush oil grooves with a certain radian are arranged symmetrically in the two ends of the inner circle surface of each bearing bush. Each bearing bush is furtherprovided with two oil passing holes enabling the bearing bush oil grooves in the two ends of the bearing bush to communicate with the annular oil groove. A journal of the crankshaft is provided with a multi-channel oil way structure capable of communicating with the bearing bush oil grooves in the bearing bushes. The crankshaft mounting structure of the opposed engine is reasonable in structure, reliable in lubrication and cooling, and convenient to maintain; and the situation that the crankshaft directly makes contact with the bearing bushes, and consequentially bush burning is caused can be avoided.