This paper proposed a new evolutionary algorithm based on concept and principles of quantum computing, called Multi-update Mode Quantum Evolution Algorithm (MMQEA), in which having two update modes á-update and β-update, and between their modes each update procedure provide its evolutionary information to other one, that to guide the other update-mode to maintain the population diversity and avoid premature. Meanwhile in MMQEA, proposed a new individual structure that composed by two Q-bit strings. Applying the multi-update mode to individual evolution improved the Q-gate updating efficiency in each generation of MMQEA. To demonstrate its effectiveness and applicability, the proposed algorithms were tested on a famous combinatorial optimization problem, the knapsack problem. The results show that MMQEA performs very well compared with Quantum Evolutionary Algorithm (QEA).