A bend-insensitive multimode optical fiber, comprising a core layer and a cladding which comprises an inner cladding, and an outer cladding arranged sequentially from inside to outside, wherein the core layer has a refractive index profile in a shape of a parabola, a distribution index α in a range of 2.0 to 2.3, a first radius in a range of 23 μm to 27 μm, and a maximum relative refractive index difference Δ1 max in a range of 0.9% to 1.2% at a center of the core layer, and the core layer is a silicon dioxide glass layer co-doped with germanium Ge, phosphorus P, and fluorine F, wherein the inner cladding has a second radius, wherein P and Ge are used as positive dopants; a contribution amount of P at the center of the core layer, ΔP0, is in a range of 0.01% to 0.30%; a contribution amount of P at a boundary of the core layer and the inner cladding, ΔP1, is in a range of 0.01% to 0.30%; a difference between the contribution amount of P at the center of the core layer and the contribution amount of P at an edge of the core layer is ΔP10, and Δ P 10 = 2 Δ P 1 − Δ P 0 ΔP 1 + ΔP 0, ΔP10 being less than or equal to 5%; and a content of P at the center of the core layer is consistent with a content of P at the edge of the core layer, and wherein F is used as a negative dopant; a doping amount of F increases from the center of the core layer to the edge of the core layer; and a contribution amount of F at the center of the core layer, ΔF0, is in a range of 0.0 % to -0.1%, and a contribution amount of F at the edge of the core layer, ΔF1, is in a range of -0.40% to -0.20%, wherein the inner cladding is a silicon dioxide glass layer co-doped with phosphorus P and fluorine F, wherein a contribution amount of doping of F, ΔF2, is in a range of -0.18% to -0.08%; a contribution amount of P at an outer edge of the inner cladding, ΔP2, is in a range of 0 % to 0.40%; and a difference between the contribution amount of P at the boundary of the core layer and the inner cladding and the contribution amount of P at the outer edge of the inner cladding is ΔP21, and ΔP21=ΔP2-ΔP1, ΔP21 being in a range of -0.3% to -0.01% or in a range of 0.01% to 0.20%, characterized in that the cladding additionally includes a depressed cladding, and that the inner cladding is divided into a platform area and a graded area from inside to outside according to variation of a concentration of P, wherein the concentration of P in the platform region remains substantially consistent, and then the concentration of P gradually increases or decreases, the platform area having a width T1 in a range of 0.1 μm to 2 μm, the graded area having a width T2 in a range of 2 μm to 4 μm; the inner cladding has a width in a range of 1.0 μm to 5.0 μm, wherein the width of the inner cladding corresponds to the difference between the second radius and the first radius; and the inner cladding has a relative refractive index difference Δ2, and Δ2=ΔP2+ΔF2, ΔF2 in the platform area and the graded area ensuring that Δ2 is in a range of -0.09% to 0.09%. wherein the inner cladding has a second radius, wherein P and Ge are used as positive dopants; a contribution amount of P at the center of the core layer, ΔP0, is in a range of 0.01% to 0.30%; a contribution amount of P at a boundary of the core layer and the inner cladding, ΔP1, is in a range of 0.01% to 0.30%; a difference between the contribution amount of P at the center of the core layer and the contribution amount of P at an edge of the core layer is ΔP10, and Δ P 10 = 2 Δ P 1 − Δ P 0 ΔP 1 + ΔP 0, ΔP10 being less than or equal to 5%; and a content of P at the center of the core layer is consistent with a content of P at the edge of the core layer, and wherein F is used as a negative dopant; a doping amount of F increases from the center of the core layer to the edge of the core layer; and a contribution amount of F at the center of the core layer, ΔF0, is in a range of 0.0 % to -0.1%, and a contribution amount of F at the edge of the core layer, ΔF1, is in a range of -0.40% to -0.20%, wherein the inner cladding is a silicon dioxide glass layer co-doped with phosphorus P and fluorine F, wherein a contribution amount of doping of F, ΔF2, is in a range of -0.18% to -0.08%; a contribution amount of P at an outer edge of the inner cladding, ΔP2, is in a range of 0 % to 0.40%; and a difference between the contribution amount of P at the boundary of the core layer and the inner cladding and the contribution amount of P at the outer edge of the inner cladding is ΔP21, and ΔP21=ΔP2-ΔP1, ΔP21 being in a range of -0.3% to -0.01% or in a range of 0.01% to 0.20%, characterized in that the cladding additionally includes a depressed cladding, and that the inner cladding is divided into a platform area and a graded area from inside to outside according to variation of a concentration of P, wherein the concentration of P in the platform region remains substantially consistent, and then the concentration of P gradually increases or decreases, the platform area having a width T1 in a range of 0.1 μm to 2 μm, the graded area having a width T2 in a range of 2 μm to 4 μm; the inner cladding has a width in a range of 1.0 μm to 5.0 μm, wherein the width of the inner cladding corresponds to the difference between the second radius and the first radius; and the inner cladding has a relative refractive index difference Δ2, and Δ2=ΔP2+ΔF2, ΔF2 in the platform area and the graded area ensuring that Δ2 is in a range of -0.09% to 0.09%.