Endoscope objective lens

The utility model discloses an endoscope objective lens, which comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens which are sequentially arranged from an object side to an imaging side, the refractive index of the first lens is 1.7 < Nd1 < 1.9, the Abbe number of the first lens is 60 < Vd1 < 80, and the first lens is made of sapphire; the refractive index of the second lens is 1.8 < Nd2 < 2.0, and the Abbe number of the second lens is 30 < Vd2 < 45; the refractive index of the third lens is 1.8 < Nd3 < 2.0, and the Abbe number of the third lens is 20 < Vd3 < 35; the refractive index of the fourth lens is that Nd4 is more than 1.4 and less than 1.7, and the Abbe number of the fourth lens is that Vd4 is more than 60 and less than 85; the refractive index of the fifth lens is 1.8 < Nd5 < 2.0, and the Abbe number of the fifth lens is 10 < Vd5 < 25; and the filtering protection slide is used for cooperating with the first lens, the second lens, the third lens, the fou