The invention discloses a high-precision quantitative adjusting screw which comprises a housing; a ball groove is formed in the housing; an odd number (n) of arc slots are formed in the ball groove, and n is greater than or equal to 7; a threaded hole is formed in the part, on one sides of the arc slots, of the housing; the threaded hole is engaged and connected with an adjusting screw part through threads; a hole is formed in one end of the adjusting screw part; balls are arranged on the two sides of the hole; a spring is arranged between the balls on the two sides; a sealing gasket is arranged at one end of the adjusting screw part; and a blocking cap is arranged on one side of the sealing gasket. The high-precision quantitative adjusting screw is subjected to design improvement on the base of a common quantitative adjusting screw, so that multiple equal partition on the adjusting amount of a circle of 14, 18 and the like can be realized, and the adjusting step length can be reducedobviously; the problem that the adjusting step length of the common quantitative adjusting screw is large is solved; a machining technology is simple; and compared with an original adjusting screw provided with 8 or other even numbers of slots, high-precision quantitative adjustment can be carried out on an adjustor simply, rapidly and accurately, and the high-precision quantitative adjusting screw is good in operability.