The main aim of this work is to comprehensively and fully understand the adsorption process characteristic of Cu²⁺, Zn²⁺, Mn²⁺ on natural diatomite in liquid/solid system, and to provide reliable theoretical basis for natural diatomite modification and application. Cu, Zn, Mn are the essential elements for the human body and plants which involved in the metabolism, but too much will be detrimental to them both. Up to now, there are many techniques which have been applied to remove metal ions from waste water, among which adsorption exhibits a particularly competitive and effective advantage for heavy metal’s removal. Diatomite is a kind of biogenic siliceous rock which was formed by the initial diagenesis and preliminary diagenesis of diatom. Because of small bulk density, large specific surface area, large quantity of micropores and its well-developed pore structure which bears a large number of active groups and a certain negative charge, diatomite exhibits the potential material for adsorption of heavy metals. There are a lot of research studying the adsorption of diatomite on Cu²⁺, Zn²⁺, Mn²⁺, much of them, however, are mainly focus on the influence factors of adsorption and the brief discussion on the kinetics of adsorption rather than exploring the characteristics in adsorption process, which make the lack of sufficient and reliable theoretical basis about the modification and application of diatomite adsorbing Cu²⁺, Zn²⁺, Mn²⁺. In view of this, the adsorption conditions, properties, behavior and characteristics of Cu²⁺, Zn²⁺, Mn²⁺ on diatomite surface were systematically studied throuhg static adsorption test. The characteristic results illustrate that adsorption density of Cu²⁺, Zn²⁺, Mn²⁺ on natural diatomite increase first and then decrease with increasing diatomite adding quantity and ion initial concentration, increase constantly with solution initial pH, and the effect of solution temperature on ion adsorption process is not obvious. The most suitable isotherm models for describing adsorption of Cu²⁺, Zn²⁺, Mn²⁺ onto natural diatomite are Langmuir, Tenkin and Freundlich; the adsorption of each ion onto natural diatomite is mainly a physical process; the adsorption reaction is easy to happen, and the control step of adsorption process is adsorption reaction happened in microporous. It can also be found that, the adsorption of Cu²⁺, Zn²⁺, Mn²⁺ onto natural diatomite can reach equilibrium in forty minutes, the adsorption kinetics fit well with the pseudo-second-order model, and the adsorption is spontaneous, endothermic and disorder enhancing. The results can provide theoretical basis and reference for the modification, application and other similar research of diatomite.