A positive electrode material, wherein the positive electrode material includes a lithium-nickel transition metal oxide A and a lithium-nickel transition metal oxide B, the lithium-nickel transition metal oxide A is secondary particles, and a chemical formula of the lithium-nickel transition metal oxide A is shown in Formula I: Li a1 (Ni b1 Co c1 Mn d1) x1 M 1-x1 O 2-e1 X e1 in Formula I, 0.95≤a1≤1.05, 0.7≤b1<0.98, 0.01≤c1<0.15, 0.01≤d1≤0.3, 0.95≤x1≤1, and 0≤e1≤0.1, wherein M is selected from any one or a combination of Al, Ti, Zr, Nb, Sr, Sc, Sb, Y, Ba, B, C, Co, and Mn, and X is selected from F and/or Cl; the lithium-nickel transition metal oxide B is monocrystalline or monocrystalline-like particles, and a chemical formula of the lithium-nickel transition metal oxide B is shown in Formula II: Li a2 (Ni b2 Co c2 Mn d2) x2 M' 1-x2 O 2-e2 X' e2 in Formula II, 0.95≤a2≤1.05, 0.7<b2<0.98, 0.01≤c2≤0.15, 0.01<d2<0.3, 0.95≤x2≤1, and 0≤e2≤0.1, wherein M' is selected from any one or a combination of Al, Ti, Zr, Nb, Sr, Sc, Sb, Y, Ba, B, C, Co, and Mn, and X' is selected from F and/or Cl; and a crystal size D 104 of the positive electrode material and a particle size distribution change rate ΔPSD of the positive electrode material satisfy: 50 nm ≤ D 104 × Δ PSD ≤ 450 nm, wherein ΔPSD is a particle size distribution change rate calculated according to the formula ΔPSD=(D v 90-D v 10)/D v 50 based on a measured particle size of volume particle distribution of the positive electrode material, and D 104 is a crystal size obtained by fitting a peak value of a 104 crystal plane through XRD ray diffraction testing on the positive electrode material measured in nm and both parameters ΔPSD and D 104 are measured according to the methods disclosed in the description; and, wherein the lithium-nickel transition metal oxide A has Dv50 of 8μm to 15μm, 8μm to 10μm, 10μm to 12μm, or 12μm to 15μm; Dv10 of 3μm to 8μm, 3μm to 5μm, or 5μm to 8μm; and Dv90 of 15μm to 25μm, 15μm to 18μm, 18μm to 20μm, or 20μm to 25μm; and, wherein the lithium-nickel transition metal oxide B has Dv50 of 1μm to 7μm, 1μm to 3μm, 3μm to 5μm, or 5μm to 7μm; Dv10 of 1μm to 3μm; and Dv90 of 5μm to 10μm, 5μm to 8μm, or 8μm to 10μm. in Formula I, 0.95≤a1≤1.05, 0.7≤b1<0.98, 0.01≤c1<0.15, 0.01≤d1≤0.3, 0.95≤x1≤1, and 0≤e1≤0.1, wherein M is selected from any one or a combination of Al, Ti, Zr, Nb, Sr, Sc, Sb, Y, Ba, B, C, Co, and Mn, and X is selected from F and/or Cl; the lithium-nickel transition metal oxide B is monocrystalline or monocrystalline-like particles, and a chemical formula of the lithium-nickel transition metal oxide B is shown in Formula II: Li a2 (Ni b2 Co c2 Mn d2) x2 M' 1-x2 O 2-e2 X' e2 in Formula II, 0.95≤a2≤1.05, 0.7<b2<0.98, 0.01≤c2≤0.15, 0.01<d2<0.3, 0.95≤x2≤1, and 0≤e2≤0.1, wherein M' is selected from any one or a combination of Al, Ti, Zr, Nb, Sr, Sc, Sb, Y, Ba, B, C, Co, and Mn, and X' is selected from F and/or Cl; and a crystal size D 104 of the positive electrode material and a particle size distribution change rate ΔPSD of the positive electrode material satisfy: 50 nm ≤ D 104 × Δ PSD ≤ 450 nm, wherein ΔPSD is a particle size distribution change rate calculated according to the formula ΔPSD=(D v 90-D v 10)/D v 50 based on a measured particle size of volume particle distribution of the positive electrode material, and D 104 is a crystal size obtained by fitting a peak value of a 104 crystal plane through XRD ray diffraction testing on the positive electrode material measured in nm and both parameters ΔPSD and D 104 are measured according to the methods disclosed in the description; and, wherein the lithium-nickel transition metal oxide A has Dv50 of 8μm to 15μm, 8μm to 10μm, 10μm to 12μm, or 12μm to 15μm; Dv10 of 3μm to 8μm, 3μm to 5μm, or 5μm to 8μm; and Dv90 of 15μm to 25μm, 15μm to 18μm, 18μm to 20μm, or 20μm to 25μm; and, wherein the lithium-nickel transition metal oxide B has Dv50 of 1μm to 7μm, 1μm to 3μm, 3μm to 5μm, or 5μm to 7μm; Dv10 of 1μm to 3μm; and Dv90 of 5μm to 10μm, 5μm to 8μm, or 8μm to 10μm. ΔPSD is a particle size distribution change rate calculated according to the formula ΔPSD=(D v 90-D v 10)/D v 50 based on a measured particle size of volume particle distribution of the positive electrode material, and D 104 is a crystal size obtained by fitting a peak value of a 104 crystal plane through XRD ray diffraction testing on the positive electrode material measured in nm and both parameters ΔPSD and D 104 are measured according to the methods disclosed in the description; and, wherein the lithium-nickel transition metal oxide A has Dv50 of 8μm to 15μm, 8μm to 10μm, 10μm to 12μm, or 12μm to 15μm; Dv10 of 3μm to 8μm, 3μm to 5μm, or 5μm to 8μm; and Dv90 of 15μm to 25μm, 15μm to 18μm, 18μm to 20μm, or 20μm to 25μm; and, wherein the lithium-nickel transition metal oxide B has Dv50 of 1μm to 7μm, 1μm to 3μm, 3μm to 5μm, or 5μm to 7μm; Dv10 of 1μm to 3μm; and Dv90 of 5μm to 10μm, 5μm to 8μm, or 8μm to 10μm.