With an attempt to solve the problems in crop harvesting including the low utilization rate of agricultural machinery and tools, header loss and poor working stability caused by vibration, we designed a new multi-crop header for combined harvesting of rice, corn and soybean for 4LZ-3.2 rice combine harvester with optimal parameters of header expansion, scion plate and linkage mechanism. The header vibration test and field harvest test were carried out. By adding a hydraulic cylinder expansion mechanism and a connecting rod linkage based scion plate transformation mechanism to meet the requirements of multi-crop harvesting, theoretical analysis determined that the header expansion length during corn harvesting was 200 mm, the scion plate had a folding angle of 15°, a total length of 300 mm, a width of 30 mm, a folding length of 135 mm, and a thickness of 5 mm. The length of connecting rod Ⅰ was 330 mm, the length of connecting rod Ⅱ was 70 mm, the length of pull rod was 530 mm, the length of rotating rod was 510 mm, and the material used for the components was Q235 steel plate. Vibration test showed that header vibration was due to harvester resonance at low engine speed(1800 r/min), and vibration source at high engine speed(2600 r/min), the reciprocating motion of cutter was the main vibration source of header. The feeding of material flow had a great influence on the vibration strength at different positions of the header by deflection, and the change of feeding amount had little influence on the vibration of header. The loss of the designed new header had little change compared with the common used header. Field header loss test showed that when the driving speed of the harvester was 0.6-1.4 m/s, the average loss rates of rice, corn and soybean field headers were 0.42%, 0.49% and 0.31%, respectively, which were lower than the relevant national standards, suggesting the adaptability of the universal header to the three crops and extending the header had a relatively small impact on crop losses.