Abstract: In traditional fish soup preparation, carp was rarely used as a raw material due to its strong earthy flavor and poor meat quality. However, Qingtian carp, cultivated through the paddy field farming method, exhibits a mild earthy flavor and soft edible scales, making it suitable for soups. To explore the flavor characteristics of Qingtian carp soup (field fish soup) and determine the optimal simmering time for peak flavor, changes in total solids, free amino acids, flavor nucleotides, and volatile compounds were analyzed using an amino acid analyzer, HPLC, GC-IMS, and electronic nose, combined with sensory evaluation (compared to traditional blackfish soup). Results indicated that the total solids content of field fish soup exceeded that of blackfish soup before 50 min of cooking. Freshness-related amino acids (aspartic acid, glutamic acid, glycine, and alanine) increased during cooking, with total free amino acid content comparable to blackfish soup. Prolonged cooking (>50 min) led to higher solids in blackfish soup but increased bitterness, negatively impacting flavor. The dominant flavor nucleotide in field fish soup was GMP (vs. IMP in blackfish soup), enhancing its umami profile. Electronic nose analysis revealed that odor intensity in field fish soup stabilized after 50 min, whereas blackfish soup attributes gradually increased (20~70 min). GC-IMS identified 41 volatile compounds in field fish soup and 46 in blackfish soup, both rich in esters and aldehydes. Field fish soup contained more phenolic compounds (preferred by consumers) and fewer fishy substances, while blackfish soup had higher ketone levels. A simmering time of 50~60 min optimizes flavor substance release and taste harmony in both soups. Qingtian carp demonstrates comparable suitability to blackfish for soup production, offering a novel option for diversifying fish soup varieties. This study provides practical insights for improving field fish soup flavor.