Smu_195c is a protein with 86 amino acids in Streptococcus mutans, a primary pathogen for human dental caries. The specific function of Smu_195c is still unknown and there are no conserved domains in it. In order to find out its function, the gene encodes Smu_195c was cloned and expressed in E. coli as N-terminally 6*His tagged recombinant protein. Two crystal forms were obtained by the hanging drop method. Form Ⅰ belongs to space group P6₁22 or P6₅2 with the unit cell parameters a = b = 62.93 Å, c = 90.63 Å, γ=120° and form Ⅱ belongs to the space group P4₁2₁2 or P4₃2₁2 with the unit cell parameters a = b= 57.97 Å, c = 103.51 Å. Crystals from the protein with His-tag belong to form Ⅰ, however, crystals from the protein without His-tag belong to both.