An image decoding method, a decoder and a storage medium are provided. The method includes: receiving code stream data, and parsing the code stream data to obtain a coding tree unit corresponding to the code stream data; parsing an i-th node of i-th layer corresponding to the coding tree unit to obtain i-th state parameter and i-th flag parameter corresponding to the i-th node; performing detection processing on the i-th node according to the i-th state parameter and the i-th flag parameter to obtain an i-th detection result; acquiring a (i+1)th node of a (i+1)th layer corresponding to the coding tree unit; continuing to perform detection processing on the (i+1)th node, and traversing all the nodes corresponding to the coding tree unit until all the coding unit data corresponding to the coding tree unit is obtained; and generating a decoded image corresponding to the code stream data.