A method for assessing video quality, comprising: determining, according to a target video, an actual quantization parameter and a critical quantization parameter of the target video; and determining quality of the target video according to the actual quantization parameter and the critical quantization parameter; characterized in that determining a critical quantization parameter of the target video comprises: determining, based on encoding type and resolution of the target video, a reference quantization parameter; and determining the critical quantization parameter according to the reference quantization parameter and the content complexity information; wherein the content complexity information comprises at least one of time complexity information and space complexity information of the target video; wherein the determining the critical quantization parameter according to the reference quantization parameter and the complexity information comprises: determining the critical quantization parameter according to the following formula: T n = T 0 ⋅ 1 + scc a 1 b 1 ⋅ 1 + tcc a 2 b 2; T n = T 0 ⋅ 1 + scc a 1 b 1; T n = T 0 ⋅ 1 + tcc a 2 b 2; T n = T 0 ⋅ a 1 ⋅ scc + b 1 ⋅ tcc + c 1; T n = T 0 ⋅ 1 + scc a 1 b 1 ⋅ tcc a 2 b 2 1 + scc a 1 b 1 ⋅ tcc a 2 b 2; T n = T 0 ⋅ 1 + scc a 1 b 1 1 + scc a 1 b 1; or T n = T 0 ⋅ 1 + tcc a 2 b 2 1 + tcc a 2 b 2 wherein T n is the critical quantization parameter, T 0 is the reference quantization parameter, scc is the space complexity information, tcc is the time complexity information, and a 1, b 1, a 2, b 2, and c 1 are constants obtained by training according to sample videos. determining, according to a target video, an actual quantization parameter and a critical quantization parameter of the target video; and determining quality of the target video according to the actual quantization parameter and the critical quantization parameter; characterized in that determining a critical quantization parameter of the target video comprises: determining, based on encoding type and resolution of the target video, a reference quantization parameter; and determining the critical quantization parameter according to the reference quantization parameter and the content complexity information; wherein the content complexity information comprises at least one of time complexity information and space complexity information of the target video; wherein the determining the critical quantization parameter according to the reference quantization parameter and the complexity information comprises: determining the critical quantization parameter according to the following formula: T n = T 0 ⋅ 1 + scc a 1 b 1 ⋅ 1 + tcc a 2 b 2; T n = T 0 ⋅ 1 + scc a 1 b 1; T n = T 0 ⋅ 1 + tcc a 2 b 2; T n = T 0 ⋅ a 1 ⋅ scc + b 1 ⋅ tcc + c 1; T n = T 0 ⋅ 1 + scc a 1 b 1 ⋅ tcc a 2 b 2 1 + scc a 1 b 1 ⋅ tcc a 2 b 2; T n = T 0 ⋅ 1 + scc a 1 b 1 1 + scc a 1 b 1; or T n = T 0 ⋅ 1 + tcc a 2 b 2 1 + tcc a 2 b 2 wherein T n is the critical quantization parameter, T 0 is the reference quantization parameter, scc is the space complexity information, tcc is the time complexity information, and a 1, b 1, a 2, b 2, and c 1 are constants obtained by training according to sample videos. determining, based on encoding type and resolution of the target video, a reference quantization parameter; and determining the critical quantization parameter according to the reference quantization parameter and the content complexity information; wherein the content complexity information comprises at least one of time complexity information and space complexity information of the target video; wherein the determining the critical quantization parameter according to the reference quantization parameter and the complexity information comprises: determining the critical quantization parameter according to the following formula: T n = T 0 ⋅ 1 + scc a 1 b 1 ⋅ 1 + tcc a 2 b 2; T n = T 0 ⋅ 1 + scc a 1 b 1; T n = T 0 ⋅ 1 + tcc a 2 b 2; T n = T 0 ⋅ a 1 ⋅ scc + b 1 ⋅ tcc + c 1; T n = T 0 ⋅ 1 + scc a 1 b 1 ⋅ tcc a 2 b 2 1 + scc a 1 b 1 ⋅ tcc a 2 b 2; T n = T 0 ⋅ 1 + scc a 1 b 1 1 + scc a 1 b 1; or T n = T 0 ⋅ 1 + tcc a 2 b 2 1 + tcc a 2 b 2 wherein T n is the critical quantization parameter, T 0 is the reference quantization parameter, scc is the space complexity information, tcc is the time complexity information, and a 1, b 1, a 2, b 2, and c 1 are constants obtained by training according to sample videos. determining the critical quantization parameter according to the following formula: T n = T 0 ⋅ 1 + scc a 1 b 1 ⋅ 1 + tcc a 2 b 2; T n = T 0 ⋅ 1 + scc a 1 b 1; T n = T 0 ⋅ 1 + tcc a 2 b 2; T n = T 0 ⋅ a 1 ⋅ scc + b 1 ⋅ tcc + c 1; T n = T 0 ⋅ 1 + scc a 1 b 1 ⋅ tcc a 2 b 2 1 + scc a 1 b 1 ⋅ tcc a 2 b 2; T n = T 0 ⋅ 1 + scc a 1 b 1 1 + scc a 1 b 1; or T n = T 0 ⋅ 1 + tcc a 2 b 2 1 + tcc a 2 b 2 wherein T n is the critical quantization parameter, T 0 is the reference quantization parameter, scc is the space complexity information, tcc is the time complexity information, and a 1, b 1, a 2, b 2, and c 1 are constants obtained by training according to sample videos.