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Leucine-rich repeat (LRR) is a structural motif has important recognition function in immune receptors, such as Tolls and NOD-like receptors (NLRs). The immune-related LRR proteins can be divided into two categories, LRR-containing proteins and LRR-only proteins. The latter contain LRR motifs while they are without other functional domains. However, the functional mechanisms of the LRR-only proteins were still unclear in invertebrates. Here, we identified a gene encoding a secretory LRR-only protein, which possessed similarity with vertebrate CD14 and was designated as <i>LvCD14L</i>, from the Pacific whiteleg shrimp <i>Litopenaeus vannamei</i>. Its transcripts in shrimp hemocytes were apparently responsive to the infection of <i>Vibrio parahaemolyticus</i>. Knockdown of <i>LvCD14L</i> with dsRNA resulted in significant increase of the viable bacteria in the hepatopancreas of shrimp upon <i>V. parahaemolyticus</i> infection. Further functional studies revealed that LvCD14L could bind to microorganisms’ PAMPs, showed interaction with LvToll1 and LvToll2, and regulated the expression of <i>LvDorsal</i> and <i>LvALF2</i> in hemocytes. These results suggest that LvCD14L functions as a pattern recognition receptor and activates the NF-κB pathway through interaction with LvTolls. The present study reveals a shrimp LvCD14L-Tolls-NF-κB signaling pathway like the CD14/TLR4/NF-κB signaling pathway in mammalians, which enriches the functional mechanism of secretory LRR-only immune receptors during pathogens infection in invertebrates.