The globally invasive cotton mealybug Phenacoccus solenopsis Tinsley, has recently invaded several Chinese regions, and continues to expand its range.  This mealybug is a polyphagous insect pest, with at least 200 host plants from 63 families, including cotton, food crops, fruits, ornamental plants, tobacco, and vegetables.  Here, we describe the first finding of P. solenopsis in Shandong Province, and investigate the abundances of its natural enemies (predator Coccinella septempunctata L. and parasitoid Aenasius bambawalei Hayat).  All three species were detected from ornamental and weed species in Linyi, Shandong, in September 2018, and were positively identified using DNA barcoding.  BLAST analysis revealed significant identity (99.38–100%) between sequences of P. solenopsis obtained in this study and those published in the past.  This invasive pest represents a major potential threat to agri-horticulture in Shandong, which is a key province of China for production and export of many vegetables, flowers, fruits, and other crops.  This mealybug species has a wide range of potential distribution in Shandong and is easily dispersed with agricultural and horticultural transport products.  Further monitoring and management strategies are required to limit the spread of this pest species.