The invention discloses a chip preparation method, a DNA or protein immobilization method, and a chip. The chip preparation method of the invention comprises performing weak passivation treatment after immobilization treatment, wherein the weak passivation treatment comprises contacting a weak passivation reaction solution containing a catalyst with a chip subjected to immobilization treatment, soas to promote binding of DNA or protein to the surface of a substrate, and to enable the DNA or protein to be sufficiently immobilized on the surface of the substrate. The preparation method of the invention increases the weak passivation treatment step after the immobilization treatment, so that the DNA or protein can be more fully immobilized on the surface of the substrate, the quality and efficiency of DNA or protein immobilization are improved, also DNA or protein is more fully immobilized, the relationship between the amount of the DNA or protein immobilized on the chip and the concentration of the DNA or protein initially added is more closely, and thus the immobilization amount of the DNA or protein is highly controllable, the repeatability is good, and a foundation is laid for preparing high-quality DNA or protein chips.