A method for colour component prediction, applied to an encoder and comprising: determining a neighbouring reference sample set of a current block, and determining a preset parameter value corresponding to the current block, the neighbouring reference sample set comprising at least one reference sample; buffering the neighbouring reference sample set and the preset parameter value to construct an input reference sample set; wherein the preset parameter value is placed after the neighbouring reference sample set; determining an input sample matrix by means of a first preset calculation model based on the input reference sample set; and performing colour component prediction on the current block according to the input sample matrix to obtain a prediction block of the current block, wherein the preset parameter value is 1<<BitDepth-1), where BitDepth represents a bit depth value corresponding to a to-be-predicted colour component of the current block, and wherein determining the input sample matrix by means of the first preset calculation model based on the input reference sample set comprises: for each value of i, performing, according to a sample corresponding to a (i+1) th position and a sample corresponding to a 0 th position in the input reference sample set, a subtraction operation by means of the first preset calculation model to obtain a respective input sample, wherein a minuend of the subtraction operation is set to be equal to the sample corresponding to the (i+1) th position in the reference sample set; and a subtrahend of the subtraction operation is set to be equal to the sample corresponding to the 0 th position in the reference sample set, and wherein i is an integer greater than or equal to 0 and less than N, N representing the number of elements contained in the input sample matrix; and forming the input sample matrix according to N input samples obtained. determining a neighbouring reference sample set of a current block, and determining a preset parameter value corresponding to the current block, the neighbouring reference sample set comprising at least one reference sample; buffering the neighbouring reference sample set and the preset parameter value to construct an input reference sample set; wherein the preset parameter value is placed after the neighbouring reference sample set; determining an input sample matrix by means of a first preset calculation model based on the input reference sample set; and performing colour component prediction on the current block according to the input sample matrix to obtain a prediction block of the current block, wherein the preset parameter value is 1<<BitDepth-1), where BitDepth represents a bit depth value corresponding to a to-be-predicted colour component of the current block, and wherein determining the input sample matrix by means of the first preset calculation model based on the input reference sample set comprises: for each value of i, performing, according to a sample corresponding to a (i+1) th position and a sample corresponding to a 0 th position in the input reference sample set, a subtraction operation by means of the first preset calculation model to obtain a respective input sample, wherein a minuend of the subtraction operation is set to be equal to the sample corresponding to the (i+1) th position in the reference sample set; and a subtrahend of the subtraction operation is set to be equal to the sample corresponding to the 0 th position in the reference sample set, and wherein i is an integer greater than or equal to 0 and less than N, N representing the number of elements contained in the input sample matrix; and forming the input sample matrix according to N input samples obtained.