[en] bet LMi is a double-lined visual binary with an orbital period of ∼39 yr. Via a simultaneous fitting to both astrometric and radial velocity measurements, we give a complete and improved orbit solution with high precision. Then, the component masses are precisely determined as 2.98 ± 0.10 M _⊙ and 1.92 ± 0.04 M _⊙ with a relative precision of ∼3%, respectively. The orbital parallax is determined to be 19.6 ± 0.2 mas, which is two times more precise than Hipparcos parallax. With the known apparent magnitudes and magnitude difference of the components, we derive the luminosity of the components as 50.7 ± 1.8 L _⊙ and 9.1 ± 4.1 L _⊙. The estimated radii of the components are 9.4 ± 0.3 R _⊙ and 3.7 ± 1.5 R _⊙.