A resource allocation indication method, comprising: sending, by a Base Station, BS, first indication information, wherein the first indication information is configured to indicate an activated Bandwidth Part, BWP, message and the activated BWP message at least comprises BWP Bandwidth, BW, information; and sending, by the BS, second indication information, wherein the second indication information is configured to indicate one or more groups of first-level Resource Block Group, RBG, sizes, each group of first-level RBG sizes comprises multiple first-level RBG sizes, and each first-level RBG size corresponds to different BWP BWs, wherein there is a corresponding relationship between the first-level RBG size and different BWP BWs, wherein the method further comprises: sending, by the BS, third indication information, wherein the third indication information is configured to indicate a part of activated BWPs selected from activated BWPs; and sending, by the BS, fourth indication information, wherein the fourth indication information is configured to indicate resource allocation and a number of bits required by the fourth indication information under different activated BWPs is a fixed value, wherein the number of the bits required by the fourth indication information is determined according to the following formula: max 1 ≤ i ≤ n ⌈ log 2 ⌈ N RB i G ⌉ ∗ ⌈ N RB i G ⌉ + 1 / 2 ⌉, or, max 1 ≤ i ≤ n ⌈ ⌈ N RB i G ⌉ / P ⌉, where G is the first-level RBG size, N RB i is a BW of an ith activated BWP, n is a number of the activated BWPs, i and n are integers and P is the second-level RBG size; when ⌈ N RB i G ⌉ is less than or equal to 12, a value of the second-level RBG size is 1; and when ⌈ N RB i G ⌉ is more than 12, the value of the second-level RBG size is 2. sending, by a Base Station, BS, first indication information, wherein the first indication information is configured to indicate an activated Bandwidth Part, BWP, message and the activated BWP message at least comprises BWP Bandwidth, BW, information; and sending, by the BS, second indication information, wherein the second indication information is configured to indicate one or more groups of first-level Resource Block Group, RBG, sizes, each group of first-level RBG sizes comprises multiple first-level RBG sizes, and each first-level RBG size corresponds to different BWP BWs, wherein there is a corresponding relationship between the first-level RBG size and different BWP BWs, wherein the method further comprises: sending, by the BS, third indication information, wherein the third indication information is configured to indicate a part of activated BWPs selected from activated BWPs; and sending, by the BS, fourth indication information, wherein the fourth indication information is configured to indicate resource allocation and a number of bits required by the fourth indication information under different activated BWPs is a fixed value, wherein the number of the bits required by the fourth indication information is determined according to the following formula: max 1 ≤ i ≤ n ⌈ log 2 ⌈ N RB i G ⌉ ∗ ⌈ N RB i G ⌉ + 1 / 2 ⌉, or, max 1 ≤ i ≤ n ⌈ ⌈ N RB i G ⌉ / P ⌉, where G is the first-level RBG size, N RB i is a BW of an ith activated BWP, n is a number of the activated BWPs, i and n are integers and P is the second-level RBG size; when ⌈ N RB i G ⌉ is less than or equal to 12, a value of the second-level RBG size is 1; and when ⌈ N RB i G ⌉ is more than 12, the value of the second-level RBG size is 2. sending, by the BS, third indication information, wherein the third indication information is configured to indicate a part of activated BWPs selected from activated BWPs; and sending, by the BS, fourth indication information, wherein the fourth indication information is configured to indicate resource allocation and a number of bits required by the fourth indication information under different activated BWPs is a fixed value, wherein the number of the bits required by the fourth indication information is determined according to the following formula: max 1 ≤ i ≤ n ⌈ log 2 ⌈ N RB i G ⌉ ∗ ⌈ N RB i G ⌉ + 1 / 2 ⌉, or, max 1 ≤ i ≤ n ⌈ ⌈ N RB i G ⌉ / P ⌉, where G is the first-level RBG size, N RB i is a BW of an ith activated BWP, n is a number of the activated BWPs, i and n are integers and P is the second-level RBG size; when ⌈ N RB i G ⌉ is less than or equal to 12, a value of the second-level RBG size is 1; and when ⌈ N RB i G ⌉ is more than 12, the value of the second-level RBG size is 2.