This study proposes a biomimetic mineralized mortar based on biomimetic-chemically induced carbonate precipitation (BCICP) method with boric acid as a crystal modifier. In particular, the reaction between calcium ions and carbonate ions is directly regulated by the modifier to achieve effective cementation and reinforcement of sand particles with high concentration cementing solution. Effects of key environmental factors on the BCICP method were investigated, including the particle sizes of cementing matrix, cementing solution pH, and magnesium ions. The results show that with the addition of smaller particle size, a more effective crystal precipitation mode could be obtained, which results in a higher calcium carbonate reinforcement efficiency. Then, the acidic environment presents a slight effect on the reinforcement efficiency of BCICP method with boric acid as the crystal modifier. However, the alkaline environment, boric acid molecules could be severely consumed, and the reinforcement efficiency significantly decreases. Moreover, with the participation of boric acid, biomimetic mineralized mortar can use a high concentration of magnesium chloride as the cementing solution to effectively reinforce sand samples, which is attributed to bridges formed by magnesium carbonate precipitation at the interparticle contacts.