A rapid, simple and sensitive ultra performance liquid chromatography-diode array detection method (UPLC-DAD) was developed and validated for quantification of four biologically important Amaryllidaceae alkaloids viz. lycoramine, hamayne, haemanthamine and tortuosine in Zephyranthes grandiflora. The method employed BEH C(18) column (2.1mm×100mm, 1.7μm particle size) with linear gradient elution of acetonitrile and water (0.05% formic acid) in a flow rate of 0.3mL/min and at λ(max) 280nm. Standard calibration curve for the analytes were linear (r(2)≥0.9999), precise (intra-day RSDs<1.33% and inter-day RSDs<2.67%) and accurate (97.8-105.3%). The developed method was applied to the quality assessment of samples collected during different seasons and showed significant variation with an optimum amounts of these alkaloids in rainy season. The method was also applied for identification of Amaryllidaceae alkaloids in the plant and overall, seventeen Amaryllidaceae alkaloids of different structural types lycorine, haemanthamine, galanthamine, narciclasine were characterised. This study provides a qualitative and quantitative method for analysis of Amaryllidaceae alkaloids.