In February of the following year, they cooperated with Heisenberg and published the famous article "About Quantum Mechanics Ⅱ" in the name of three people, which extended the quantum mechanics developed according to Heisenberg's way to systems with any number of degrees of freedom, completed the perturbation theory of non-simple systems and a large class of simple systems, and derived the conservation laws of momentum and angular momentum, selection rules and strength formulas. Finally, the theory is applied to the statistical problem of eigenvibration of blackbody cavity. In this paper, Heisenberg's original thought has been greatly developed in matrix form, and finally a complete system of quantum mechanics in matrix form has been formed. It is a new mechanical system based on particle images of microscopic objects. Because it uses matrix mathematics, it is also called matrix mechanics. Soon, Pauli first applied this new mechanics to the spectrum of hydrogen atoms and calculated the steady-state energy value of hydrogen atoms. The results are completely consistent with Bohr's conclusion, thus confirming the correctness of the new theory. Then, physicists used quantum mechanics to deal with many puzzling atomic problems in the past, and they all succeeded. As a result, Gottingen's victory soon spread in physics. Einstein said humorously, "Heisenberg laid a lot of eggs." Cambridge, Berlin and Copenhagen all invited Heisenberg to talk about his new quantum mechanics.