techniques have been proposed and developed. [10][11][12][13][14] Among them, the fluorescent label may be more prominent with its easy fabrication, low cost, and high yield. Diverse fluorescent materials have been introduced to fabricate fluorescent labels, including organic quantum dots (QDs), [15][16][17] inorganic QDs, [18,19] and rareearth compounds. [20][21][22] Owing to their exotic photo-physical characteristics: tunable bandgap, [23] high visible-light absorption, [24] and high quantum yield, [25,26] perovskite materials have been the promising candidate for optoelectronic devices, which could help the fluorescent label with its value in the anti-counterfeiting of information security. However, the poor stability of perovskite materials within the ambient conditions, especially under humidity, remains the obstacle to their widespread applications. Several strategies have been put forward to improve the stability, such as composition modulation, [27] surface passivation, [28] and matrix encapsulation. [29,30] Thereinto, the matrix encapsulation with compact polymer chain could effectively shelter perovskite materials from water molecular. Zhou and co-workers have enhanced the humidity stability and thermal stability of perovskite composite film by embedding perovskite nanocrystals (NCs) in polymer matrix. [30] Meantime, the photoluminescence (PL) was also enhanced due to the in-situ formation of perovskite NCs in polymer matrix. [31] Hydrophobic polyvinylidene fluoride (PVDF) was introduced to improve the stability of perovskite fluorescent labels in water, saline, ethanol, dichloromethane and so on. After 120 h in water, the fabricated fluorescent labels still maintained the almost original fluorescent intensity, which exhibited its high stability.In addition, the fabrication of well-patterned perovskite arrays remains to be challenging, which sets limits in the applications of those flexible and ultrathin fluorescent labels. Generally, patterned perovskite arrays could be synthesized via anodized aluminum (AAO) template, [32] epitaxial growth, [33] and chemical vapor deposition, [34,35] which are not suitable for perovskite/PVDF composite films due to the decomposition under severe environment such as organic solvent or high temperature in the fabrication process. Therefore, a feasible fabrication protocol for patterned perovskite arrays of flexible and ultrathin fluorescent labels is most expected.As an essential part of information security in the Internet of Things (IoT), fluorescent labels possess a principal portion of anti-counterfeiting due to its easy fabrication, low cost, and high yield. Here an ultrathin, stable, and patterned multi-color fluorescent label with perovskite/polyvinylidene fluoride composite film is presented, which registers a resolution of 56.4 dpi and almost maintains its original fluorescent intensity after being immersed in water for 120 h. The variable color of fluorescent labels will improve the anticounterfeiting dimensions for the information security due to precise hal...