We report spectroscopic measurements on the 6S6P3P1 level of Lu+ at 28503.16 cm−1. The radiative lifetime of this level was measured to be 37.4 ± 1.9 ns using time-resolved laser-induced fluorescence of a slow ion beam. Branching fractions were determined from Lu spectra recorded using the 1.0 m Fourier transform spectrometer at the National Solar Observatory. The log(gf) values determined by combining the radiative lifetime and branching fractions for the λ3507.39, λ5983.90, and λ6221.87 (air wavelengths) lines are −1.16 ±0.03, −1.16 ±0.06, and −0.76 ±0.04, respectively. The λ6221.87 line has been identified by Bord, Cowley, and Mirijanian (1997) as the best candidate for the determination of the solar lutetium abundance because it is only slightly blended in the solar spectrum. The present λ 6221.87 transition probability measurement brings their solar lutetium abundance into good agreement with the CI chondrite abundance.