Our goal is the preparation and study of ultracold plasma and Rydberg matter. We assembled an experimental setup for laser cooling of lithium atoms in a magneto-optical trap (MOT). Trapping of 7Li atoms in a MOT is demonstrated for a wide range of cooling laser detunings. The number density of 7Li atoms at different ground-state sublevels is measured by using a probe tunable laser. The temperature of the trapped atoms is estimated. Obtained information is important for the preparation of ultra-cold plasma and highly-excited atoms.