An optical system, comprising: a third lens , a second lens and a first lens arranged successively along a propagation direction of incident light; an effective focal length f1 of the first lens is 20mm ≤ f1 ≤ 40mm, an effective focal length f2 of the second lens is 20mm ≤ f2 ≤ 40mm, and an effective focal length f3 of the third lens is -75mm ≤ f3 ≤ -35mm, the first lens comprises a first surface and a second surface , and the second lens comprises a third surface and a fourth surface ; the second surface and the third surface are arranged adjacent to each other and are both set as Fresnel surfaces and at least one of the Fresnel surfaces has a curved base; and the first surface and the fourth surface are both aspherical surfaces, the absolute value of the radius R1 of the first surface of the first lens satisfies 45mm ≤ Abs (R1) ≤ 65mm; the absolute value of the radius R0 of the curved base on the second surface of the first lens satisfies 40mm ≤ Abs (R0) ≤ 200mm, and the absolute value of the radius R2 of the second surface satisfies 20mm ≤ Abs (R2) ≤ 40mm; the absolute value of the conic constant K1 of the first surface and the second surface of the first lens satisfies Abs (K1) ≤ 10, the absolute value of the radius R0' of the curved base on the third surface satisfies 60mm ≤ Abs (R0') ≤ 170mm, and the absolute value of the radius R3 of the third surface satisfies 20mm ≤ Abs (R3) ≤ 40mm; the absolute value of the radius R4 of the fourth surface satisfies 60mm ≤ Abs (R4) ≤ 80mm; the absolute value of the conic constant K2 of the third surface and the fourth surface 22 of the second lens 2 satisfies Abs (K2) ≤ 10. a third lens , a second lens and a first lens arranged successively along a propagation direction of incident light; an effective focal length f1 of the first lens is 20mm ≤ f1 ≤ 40mm, an effective focal length f2 of the second lens is 20mm ≤ f2 ≤ 40mm, and an effective focal length f3 of the third lens is -75mm ≤ f3 ≤ -35mm, the first lens comprises a first surface and a second surface , and the second lens comprises a third surface and a fourth surface ; the second surface and the third surface are arranged adjacent to each other and are both set as Fresnel surfaces and at least one of the Fresnel surfaces has a curved base; and the first surface and the fourth surface are both aspherical surfaces, the absolute value of the radius R1 of the first surface of the first lens satisfies 45mm ≤ Abs (R1) ≤ 65mm; the absolute value of the radius R0 of the curved base on the second surface of the first lens satisfies 40mm ≤ Abs (R0) ≤ 200mm, and the absolute value of the radius R2 of the second surface satisfies 20mm ≤ Abs (R2) ≤ 40mm; the absolute value of the conic constant K1 of the first surface and the second surface of the first lens satisfies Abs (K1) ≤ 10, the absolute value of the radius R0' of the curved base on the third surface satisfies 60mm ≤ Abs (R0') ≤ 170mm, and the absolute value of the radius R3 of the third surface satisfies 20mm ≤ Abs (R3) ≤ 40mm; the absolute value of the radius R4 of the fourth surface satisfies 60mm ≤ Abs (R4) ≤ 80mm; the absolute value of the conic constant K2 of the third surface and the fourth surface 22 of the second lens 2 satisfies Abs (K2) ≤ 10. <EOS>