An ECG lossless compression system comprises: a signal difference value generating module and a compression module. The signal difference value generating module executes an adaptive linear prediction coding to an ECG signal, so as to generate a plurality of signal difference values corresponded to each data of the ECG signal； the compression module divides the signal difference values into a plurality of groups, and executes an lossless compression coding to the groups, so as to generate a plurality of window compression streams, wherein each group is corresponding to a bit reference index configured to be a compression coding parameter of the lossless compression coding.一種無損心電訊號壓縮系統，包含：訊號差值產生模組及壓縮模組。訊號差值產生模組對心電訊號進行一可變動式預測編碼，進而產生心電訊號的每筆資料所對應的訊號差值；壓縮模組將該等訊號差值分為複數個群組，並利用一可變動式無損壓縮編碼對每個群組進行編碼，進而產生複數個視窗壓縮串流，其中每個群組對應一位元參考指標，且每個位元參考指標是被設定為可變動式無損壓縮編碼的壓縮編碼參數。
