The present disclosure relates to a hydroformylation catalyst, a catalyst composition containing the same, and a method for preparing an aldehyde by using the same, and has effects of providing: a hydroformylation catalyst lowering the normal/iso (n/i) ratio of an aldehyde to be generated, increasing the yield of a synthetic gas, and having excellent catalytic activity and stability during a hydroformylation reaction of an olefin-based compound; a catalyst composition containing the same; and a method for preparing an aldehyde by using the same.