A method for picture prediction, implemented in a decoder and comprising: determining at least two colour components of a current block in a picture, wherein the at least two colour components comprise a first colour component and a second colour component; constructing a prediction model according to a reference value of the first colour component of the current block and a reference value of the second colour component of the current block, wherein the prediction model uses the first colour component for performing cross-component prediction on the second colour component; characterised in that the reference values are obtained by: performing characteristic statistics on the at least two colour components of the current block, wherein the characteristic statistics are suitable for distinguishing colour components with rich texture from flat colour components; obtaining an initial reference value of the first colour component and an initial reference value of the second colour component based on values of neighbouring samples of the current block; and pre-processing, according to a result of characteristic statistics, the initial reference values, wherein the pre-processing comprises filtering to balance the statistical characteristics of the first colour component and the second colour component. determining at least two colour components of a current block in a picture, wherein the at least two colour components comprise a first colour component and a second colour component; constructing a prediction model according to a reference value of the first colour component of the current block and a reference value of the second colour component of the current block, wherein the prediction model uses the first colour component for performing cross-component prediction on the second colour component; characterised in that the reference values are obtained by: performing characteristic statistics on the at least two colour components of the current block, wherein the characteristic statistics are suitable for distinguishing colour components with rich texture from flat colour components; obtaining an initial reference value of the first colour component and an initial reference value of the second colour component based on values of neighbouring samples of the current block; and pre-processing, according to a result of characteristic statistics, the initial reference values, wherein the pre-processing comprises filtering to balance the statistical characteristics of the first colour component and the second colour component. performing characteristic statistics on the at least two colour components of the current block, wherein the characteristic statistics are suitable for distinguishing colour components with rich texture from flat colour components; obtaining an initial reference value of the first colour component and an initial reference value of the second colour component based on values of neighbouring samples of the current block; and pre-processing, according to a result of characteristic statistics, the initial reference values, wherein the pre-processing comprises filtering to balance the statistical characteristics of the first colour component and the second colour component.