A method of adjusting bolt-hole clearance and bolt torqued is proposed to improve the pin-load distribution in multi-bolt composite joints. First of all, based on the improved pin-load distribution measurement method, the multiple linear regression function of each pin-load ratio is obtained by SPSS and a linear optimization model is established with the bolt-hole clearance and bolt torque as design variables. Then, the optimization model is solved by simplex algorithm, obtaining the optimal solution. At last, the three-bolt, single-lap joint is taken as an example to compare the calculation and experimental results. The results show that the calculated optimization results agree well with the experimental results. After optimization, the maximum pin-load proportion decreases dramatically from 36.06% to 33.45％; the bearing capacity of the three-bolt, single-lap joints has increased by 10.8%; and the structure failure has been improved to pin-hole bearing failure.
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