The nucleophilic reaction of ambident β-lactam carbenes with alkylphenylketenes is studied, which produces two types of spiro[β-lactam-2,1′-indene] derivatives in total yields of 55–89 %. This work not only provides the first example that ambident carbenes behave with high activity towards ketenes, but also developes the application of β-lactam carbenes in the construction of spiro-β-lactam compounds.