Based on existing relevant scientific literatures, the review summarizes the impact factors of the degradation heavy metal ions and organic contaminants by titanium dioxide photocatalysis. The factors affecting photocatalytic activity include titanium dioxide crystal configuration, type of light irradiation and light intensity, pH value, oxygen, dosage of titanium dioxide, reactant concentration, reaction temperature, and some inorganic anions. The recent research progresses made in the mechanism of photocatalysis degradation heavy metal ions and organic contaminants is elaborated. The applications of research progresses including the impact of metal ions on the rate of photocatalytic oxidation of organic contaminants, the impact of organic contaminants on the rate of photocatalytic reduction of the heavy metals, and synergistic interaction between removal of metals and degradation of organic contaminants by photocatalysis are presented as well. At last, the difficulties involving feature research are analyzed and further investigations and applications of heavy metals and organic contaminants by titanium dioxide photocatalysis are pointed out.