The invention provides a low-cost method for improving the nickel-cobalt leaching rate of low-grade lateritic nickel ore. In the method, laterite ore is roasted twice, wherein primary roasting is hermetically carried out for about 30 minutes at a temperature between 90 and 110 DEG C, and secondary roasting is carried out for about 1 hour at a temperature between 260 and 420 DEG C under the condition with air supply, so as to change the phase structure of nickel-cobalt-containing metal in mineral, ensure that the nickel-cobalt-containing metal is easier to leach by leaching agents and raise the nickel-cobalt leaching rate with low acid consumption at a low temperature. At the same time of roasting, the method changes the existence structure of iron, increases leaching activation energy, and reduces the leaching of iron. A roasting material is cooled to about 50 DEG C in air, and leaching is carried out by adding sulfuric acid or hydrochloric acid at about 50 DEG C. The leaching rate ofnickel and cobalt can reach 93 percent and 87 percent, and the leaching rate of iron can be reduced to about 30 percent at most.