The invention discloses a method for evaluating the autonomous performance of unmanned boats. The method includes steps of 1), preparing test tools; 2), selecting water areas; 3), evaluating the performance including the autonomous path planning performance, the autonomous path tracking performance and the autonomous collision avoiding performance; 4), respectively evaluating the autonomous path planning performance, the autonomous path tracking performance and the autonomous collision avoiding performance by the aid of dimensionless formulas. Autonomous path planning, autonomous path tracking and autonomous collision avoiding are repeatedly carried out by n times, and accordingly the ultimate autonomous path planning performance, the ultimate autonomous path tracking performance and the ultimate autonomous collision avoiding performance can be obtained according to the single autonomous path planning performance, the single autonomous path tracking performance and the single autonomous collision avoiding performance. The method has the advantages that lengths and time, track error sums and time and track lengths and time which are already converted into dimensionless parameters are proportionally combined with one another, accordingly, the autonomous performance of the unmanned boats can be comprehensively evaluated by the aid of weight distribution combinations, particular evaluation processes are proposed, and the method is concise, feasible, scientific and reasonable.