The effects of different laser power and scanning speed on the surface morphology and roughness of single track CuSn10 thin-walled side surface fabricated by SLM were studied in this paper. Moreover, the optimized manufacturing process was obtained. Double track CuSn10 thin-walled parts were fabricated by the above process, and the effects of different scanning space on the surface roughness of the two forming sides were studied. Taking the above scanning space as the contour offset, 0.5 mm thin-walled parts were fabricated with two scanning strategies of long linear scanning filling and short linear scanning filling. Results show that when the laser power is 195 W and the scanning speed is 550 mm/s, the minimum average roughness of single track thin-walled parts is 2.3 μm±0.2 μm. With the increase of scanning space, the roughness of the second forming surface decreases. When the scanning space is 120 μm, 140 μm, 160 μm, the interaction between the two parallel melting is low, and the effect on the roughness is small. The short linear scanning filling has a lower surface roughness value than the long linear scanning filling. When the offset is 160 μm, the minimum average roughness value of the side surface of the thin-walled part manufactured by short linear scanning filling is 2.27 μm±0.4 μm.