The present invention discloses a catalyst for preparing pyridine base from syngas. The catalyst includes a carrier, an active component, a first auxiliary and a second auxiliary. The carrier is molecular sieves. The active component is Rh. The first auxiliary is one or more of Mn, Fe, Na and La. The second auxiliary is one or more of Zn, Co, Cr, Bi and Cu. The active component Rh is 0.5-3% of a mass of the carrier. The first auxiliary is 0.05-5% of the mass of the carrier. The second auxiliary is 0.5-15% of the mass of the carrier. The present invention further discloses application of the catalyst to preparation of pyridine base by catalyzing syngas, where the syngas and an ammonia donor are used as reaction raw materials for reaction to generate pyridine base products. The catalyst of the present invention can couple a cyclization reaction of generating acetaldehyde through hydrogenation of carbon monoxide with a condensation reaction of aldehyde and ammonia to convert the syngas into the pyridine base through one-step catalysis, with a carbon monoxide conversion rate of 8-20% and a pyridine base selectivity of 10-18%.