Solution and kit capable of stably preserving NADH

The present invention provides a solution and a kit capable of stably preserving NADH (a reduced form of nicotinamide-adenine dinucleotid). The solution comprises the following components: 50-200 mmol/L of buffer salt, 50-300 mmol/L of chloride salt, and 1.5-7.5 mmol/L of a chelating agent. According to the solution capable of stably preserving NADH provided by the present invention, based on adding a chelating agent and a preservative, the chloride salt is used in a cooperative manner, so that the stability of NADH can be significantly improved; and when the solution for preserving NADH is placed at 37 DEG C for 7 days, the relative content of the solution is kept above 92%, and when the solution is placed for 14 days, the relative content is kept above 85%, so that compared with the preservation method by using the low-concentration Tris solution, the solution provided by the present invention has higher stability and a longer lasting effect, and can be applied to the detection of various substances, and ha